Low power and Lossy Networks (LLNs), e.g., sensor networks, have a myriad of applications, such as Smart Grid and Smart Cities. Various challenges are presented with LLNs, such as lossy links, low bandwidth, battery operation, low memory and/or processing capability, etc. For example, shared-media communication networks, such as power-line communication (PLC) networks (a type of communication over power-lines), provide an enabling technology for networking communication and can be used for example in Advanced Metering Infrastructure (AMI) networks, and are also useful within home and buildings. Interestingly, PLC lines share many characteristics with low power radio (wireless) technologies. In particular, though each device in a given PLC network may each be connected to the same physical power-line, due to their noisy environment, a PLC link is very much a multi-hop link, and connectivity is highly unpredictable, thus requiring multi-hop routing when the signal is too weak.
Many LLNs, particular AMI networks, demand that many different applications operate over the network, such as sensor reading, firmware upgrades, alarms, and so on. Generally speaking, these different applications have significantly different traffic characteristics, for example, unicast vs. multicast, small units of data vs. large units of data, low-latency vs. latency-tolerant, flows toward a head-end vs. away from the head-end, etc. Furthermore, since these applications must operate simultaneously over a highly constrained LLN network, the network can easily experience congestion, especially when different applications are sending traffic simultaneously. Without proper mechanisms, these situations can cause networks to violate critical service level agreements (SLAs), e.g., delaying the reception of critical alarms from a meter or a sensor. Accordingly, Quality of Service (QoS) mechanisms are a critical functionality in shared-media communication networks, particular the highly constrained LLNs.